Perhaps you should try some spelling variations:
ban banh » ban hanh, ban anh, ban danh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cac cuc » cac cuoc, cac cua, cac nuoc
cuc ban » cua ban, cac ban, cuu ban
banh de » hanh de, banh keo, thanh de
cua tu » cua tuc, cua cu, cua te
cua su » qua su
x hoi » o hoi, x ho, 5 hoi

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((x hoi) or (xa hoi)). hieu va cac cuc ban banh de ((cua tu) OR (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (xa hoi)). hieu va cac cuc ban banh de ((cua tu) OR (cua su)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) or (xa hoi)). hieu va cac cuc ban banh de ((cua tu) OR (cua su))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (xa hoi)). hieu va cac cuc ban banh de ((cua tu) OR (cua su))*.